IFC 4.3.x development

8.9.3.50 IfcPointOnCurve

8.9.3.50.1 Semantic definitions at the entity

The IfcPointOnCurve is a point defined by a parameter value of its defining curve.

NOTE  Definition according to ISO/CD 10303-42:1992
A point on curve is a point which lies on a curve. The point is determined by evaluating the curve at a specific parameter value. The coordinate space dimensionality of the point is that of the basis curve.

NOTE  Entity adapted from point_on_curve in ISO 10303-42.

HISTORY  New entity in IFC2x2.

Informal Propositions:

  1. The value of the point parameter shall not be outside the parametric range of the curve.

8.9.3.50.1 Attributes

# Attribute Type Description
IfcRepresentationItem
LayerAssignmentSET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItemsAssignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.

> IFC2x3 CHANGE  The inverse attribute LayerAssignments has been added.

> IFC4 CHANGE  The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.
StyledByItem SET [0:1] OF IfcStyledItem FOR Item Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.



> IFC2x3 CHANGE  The inverse attribute StyledByItem has been added.
IfcGeometricRepresentationItem
IfcPoint
IfcPointOnCurve
1 BasisCurve IfcCurve The curve to which point parameter relates.
2 PointParameter IfcParameterValue The parameter value of the point location.
Dim INVALID The space dimensionality of this class, determined by the space dimensionality of the basis curve.

8.9.3.50.2 Entity inheritance

dot_inheritance IfcPointOnCurve IfcPointOnCurve IfcPoint IfcPoint IfcPointOnCurve->IfcPoint IfcPoint_children 3 more... IfcPoint_children->IfcPoint IfcGeometricRepresentationItem IfcGeometricRepresentationItem IfcPoint->IfcGeometricRepresentationItem IfcGeometricRepresentationItem_children 24 more... IfcGeometricRepresentationItem_children->IfcGeometricRepresentationItem IfcRepresentationItem IfcRepresentationItem IfcGeometricRepresentationItem->IfcRepresentationItem IfcRepresentationItem_children 3 more... IfcRepresentationItem_children->IfcRepresentationItem

8.9.3.50.3 Formal representations

ENTITY IfcPointOnCurve
 SUBTYPE OF (IfcPoint);
	BasisCurve : IfcCurve;
	PointParameter : IfcParameterValue;
 DERIVE
	 Dim : IfcDimensionCount := BasisCurve.Dim;
END_ENTITY;